This paper deals with the dimensional stability of paper containing high-yield pulps. The water retention value of some high-yield pulps, hardwood bleached kraft pulp (LBKP) and stone ground wood (SGP), the wet expansivity of the sheets and the effect of drying conditions on the sheets were studied. The results obtained are summerized as follows.
(1) The wet expansivity of the sheet made from hardwood high-yield pulps with a yield 82 to 85%, in spite of low density, was as large as that of the sheet from LBKP. This result was found to be caused by the high water retention value of the fines fractions in those high-yield pulps.
(2) During drying without tension, the shrinkage of the high-yield pulp sheets was equal to that from the LBKP sheet. But the shrinking stress of the sheets was much smaller than that of the LBKP sheet. For that reason the shrinkage of the sheet from those high-yield pulps was very dependent on the tension during drying.
(3) The dimensional stability of the paper containing high-yield pulps was more affected by the drying conditions on the paper machine.

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A large number of studies on the factors affecting the dimensional stability and curl of paper, and their mechanism have been carried out to date from the physical viewpoint, and they have given us nearly all phases of fundamental knowledge on the problem. However, arrival at a solution to curl in the mill site by applying these theoretical studies is not easy. Papermakers have tried to solve the problem and are often in a difficulty in the mill because too many factors are involved in the papermaking process, which add to the two-sidedness of the sheet. Antagonistic and/or synergistic interactions of these factors vary according to each mill depending upon the papermaking conditions employed, and these interactions sometimes lead papermaking engineers to take wrong actions. Thus, it is difficult to find a solution to curl problems.
Under these circumstances, this paper deals with theoretical studies on curl by summarizing the works of W. Gally, A. Tydeman and so on. It is imperative to understand their theories in order to find a remedy to the problem in the mill site.
This paper also introduces three reports on actual papermaking experiences on curl, and finally presents the author's own theory and proposal to eliminate the curl of paper.

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本作品は工芸品のひとつである「貼り箱」の製造コストを寸法、材料、製造方法、加工の有無などから計算するWEBアプリケーションである。経験則ではなく計算モデルに基づいて製造コストを算出したいという貼り箱職人の思いに応えるため、箱の設計に合わせて必要な作業工程と作業工程ごとの人件費を計算するアルゴリズムを開発した。貼り箱の製造フローを視覚的に表現したインタフェースデザインにより、単に自動的に見積もり金額が算出されるのではなく、貼り箱職人がなぜその価格になるのかを説明できるようになることを目指した。
本作品は貼り箱製造会社Ｍ社との協働デザインの成果物であり、デザイナーの参与を通して本作品のデザインプロジェクトが始まった。Ｍ社が抱える悩みに対してＭ社のメンバーの専門性とデザイナーの専門性を活かしあうことでアプローチしたデザインプロセスが特徴である。

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